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From:   Andi Kleen <ak@linux.intel.com>
To:     Changbin Du <changbin.du@gmail.com>
Cc:     Jiri Olsa <jolsa@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Namhyung Kim <namhyung@kernel.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 0/2] perf: add support for logging debug messages to file
References: <20191126143720.10333-1-changbin.du@gmail.com>
Date:   Tue, 26 Nov 2019 12:19:11 -0800
In-Reply-To: <20191126143720.10333-1-changbin.du@gmail.com> (Changbin Du's
        message of "Tue, 26 Nov 2019 22:37:18 +0800")
Message-ID: <87v9r6e6gw.fsf@linux.intel.com>
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Changbin Du <changbin.du@gmail.com> writes:

> When in TUI mode, it is impossible to show all the debug messages to
> console. This make it hard to debug perf issues using debug messages.
> This patch adds support for logging debug messages to file to resolve
> this problem.

This was already solved in

commit f78eaef0e0493f6068777a246b9c4d9d5cf2b7aa
Author: Andi Kleen <ak@linux.intel.com>
Date:   Fri Nov 21 13:38:00 2014 -0800

    perf tools: Allow to force redirect pr_debug to stderr.

    When debugging the tui browser I find it useful to redirect the
    debug
        log into a file. Currently it's always forced to the message
    line.

    Add an option to force it to stderr. Then it can be easily
    redirected.
    
You can do

perf report --debug stderr 2> file ...

-Andi